Discount Calculator
Calculate sale prices, savings, and stack multiple discounts. Supports GBP, USD, and EUR.
Enter the original price and discount percentage to instantly see the sale price and how much you save.
Stack multiple discounts — supports GBP, USD, and EUR.
Discount Calculator
How Stacked Discounts Actually Work
Here's the trap most shoppers fall into: a 30% discount plus a 20% discount does NOT equal 50% off. Discounts stack multiplicatively, not additively. Each discount applies to the already-reduced price, not the original.
Take a £100 item with 30% off then 20% off. First discount: £100 × 0.70 = £70. Second discount: £70 × 0.80 = £56. You saved £44 — that's 44% off, not 50%. The difference grows with bigger discounts and more layers.
The maths: multiply the remaining percentages together. 70% × 80% = 56%, meaning you pay 56% of the original price. The effective discount is 100% − 56% = 44%. This calculator handles all of this automatically, even with three or four stacked codes.
Discount Equivalents at a Glance
| Discount | You Pay | On £100 | Equivalent Fraction |
|---|---|---|---|
| 10% off | 90% | £90 | 9/10 |
| 20% off | 80% | £80 | 4/5 |
| 25% off | 75% | £75 | 3/4 |
| 33% off | 67% | £67 | 2/3 |
| 40% off | 60% | £60 | 3/5 |
| 50% off | 50% | £50 | 1/2 |
| 75% off | 25% | £25 | 1/4 |
What this means for you: The fraction column is useful for quick mental maths. "25% off" means you pay three-quarters. "33% off" means you pay two-thirds. If a £60 item has 25% off, you're paying three-quarters: £60 × ¾ = £45.
Common Stacked Discount Results
| First Discount | Second Discount | Effective Total | NOT the Same As |
|---|---|---|---|
| 10% | 10% | 19% off | 20% off |
| 20% | 10% | 28% off | 30% off |
| 20% | 20% | 36% off | 40% off |
| 30% | 20% | 44% off | 50% off |
| 40% | 20% | 52% off | 60% off |
| 50% | 20% | 60% off | 70% off |
What this means for you: That "extra 20% off sale items" at the checkout isn't as generous as it sounds. On a 30% sale item, you're getting 44% off total — not 50%. Still a good deal, but worth knowing the real number before you buy.
Pricing Psychology You Should Know
Anchor Pricing
When you see "Was £200, Now £120," the £200 is the anchor. It makes £120 feel like a bargain — even if the item was never widely sold at £200. Always research the typical price before assuming a discount is genuine.
Charm Pricing
£9.99 instead of £10 works because your brain processes the first digit first. Studies show items priced at .99 outsell identical items at round numbers by 24%. You know it's a trick — and it still works.
"Up to 70% Off"
The "up to" is doing all the heavy lifting. It means one item somewhere has 70% off. The average discount across the sale is usually much lower — typically 20–30%. Check the actual discount on the specific item you want.
Buy One Get One "Free"
BOGOF is mathematically identical to 50% off when you buy two — but it makes you buy more than you planned. If you only need one, you're spending money on an item you didn't want. The best discount is on the thing you were already going to buy.
Related Money Tools
How to use this tool
Enter the original price
Add one or more discount percentages
See the final price and total savings
Common uses
- Checking how much you save during seasonal sales
- Stacking coupon codes to find the true final price
- Comparing discounts across retailers before buying
- Working out trade or wholesale discount pricing
- Verifying marked-down prices at checkout
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